Coronavirus and Blood Type: How Your Blood Type Affects Coronavirus Risk

Note: This article was written by Dr. Brandon Colby MD during the COVID-19 pandemic and references studies published in October and December 2020. The scientific understanding of COVID-19 has continued to evolve since publication. The research described below reflects the state of knowledge at the time of writing.

By Dr. Brandon Colby MD, a medical expert specializing in precision medicine.

The Link Between Blood Type and COVID-19

Is there a connection between coronavirus risk, COVID-19 severity, and blood type? Studies published in 2020 further supported the growing body of scientific evidence that individuals with blood type O may have a lower risk of infection, while those with blood type A or AB may have an increased risk of a more severe, life-threatening COVID-19 infection.

What Is Blood Type?

Blood type is a classification of blood identified by antibodies and inherited antigenic substances. Scientists identified that people have different types of blood, and there are four main blood types:

• A
• B
• AB
• O

Knowing your blood type can be medically important. Blood transfusions from people with incompatible blood types can be fatal, which is why knowing your blood type matters beyond academic curiosity.

What Do the Studies Show?

A Danish study of more than 473,000 people who were tested for COVID-19 found that people with blood type O were significantly less likely to test positive for COVID-19. A separate study of 95 critically ill COVID-19 patients found that 84 percent of those with blood type A or AB required mechanical ventilation, compared to only 61 percent of those with O or B blood types.

A Canadian study also found that people with type A or AB blood had to stay in the intensive care unit longer than those with O or B blood types: 13.5 days versus 9 days.

Dr. Mypinder Sekhon, clinical assistant professor in the Division of Critical Care Medicine and Department of Medicine at the University of British Columbia, points out that blood type O individuals are less prone to coagulation problems in the blood. Clotting was a major factor in the severity of COVID-19, which strengthens the evidence linking blood type to coronavirus outcomes.

Ethnicity and Blood Types: Coronavirus Risk

Blood type is 100% determined by a person's genes. Since many countries have a larger proportion of people with one or two blood types, variation in COVID-19 outcomes between countries may be partly related to the distribution of blood types in their populations. The Danish study found that those with blood type O were significantly under-represented among those who tested positive for COVID-19.

Blood Type and Other Health Conditions

Beyond COVID-19, blood type has been associated with risk for a range of other health conditions:

• Type A: Higher risk of stomach cancer and heart disease; women have a higher chance of suffering from ovarian cancer
• Type AB: Increased risk of heart disease; pregnant women are more likely to develop preeclampsia
• Type O: Low risk of pancreatic cancer, low risk of dying from malaria, more likely to suffer from ulcers

Blood Type and Diet

Since blood type has so much to do with the immune system and medical conditions, some evidence suggests that a blood type diet may be effective in weight management.

People with blood type A often have sensitive immune systems. The blood type diet suggests these individuals avoid meat and concentrate on fruits and vegetables. Blood type B individuals should base their diet on green vegetables, eggs, pork, beef, and low-fat dairy products while avoiding chicken. Type AB individuals should avoid caffeine, alcohol, and smoked or cured meats. Type O individuals are suggested to eat a high-protein diet rich in lean meats and low in grains.

Discover Your Blood Type and Genetic Health Profile

Knowing your blood type can help you take better care of your body, including taking the necessary precautions to reduce the risk of conditions associated with your blood type.

If you already have DNA data from 23andMe, AncestryDNA, MyHeritage, Family Tree DNA, or Living DNA, you can upload your raw DNA data to Sequencing for free and access blood type and health analysis through the Partner Marketplace.

Sequencing's Privacy First policy ensures your data is never sold or shared with anyone. You own your data and can access, download, and permanently delete it at any time, for any reason, and for free.

For those who have not yet taken a DNA test, Sequencing's whole genome sequencing reads 100% of your DNA across over 30,000 genes. Order your kit today and discover your complete genetic health picture.

About the Author

Dr. Brandon Colby MD is a US physician specializing in the fields of genetic testing and personalized preventive medicine. He is the author of Outsmart Your Genes and the founder of Sequencing.

References

• "Reduced prevalence of SARS-CoV-2 infection in ABO blood group O" by Mike Bogetofte Barnkob, et al., 14 October 2020, Blood Advances. DOI: 10.1182/bloodadvances.2020002657.
• "The association of ABO blood group with indices of disease severity and multiorgan dysfunction in COVID-19" by Ryan L. Hoiland, et al., 14 October 2020, Blood Advances. DOI: 10.1182/bloodadvances.2020002623.
• "Genomewide Association Study of Severe Covid-19 with Respiratory Failure" by The Severe Covid-19 GWAS Group, 15 October 2020, New England Journal of Medicine. DOI: 10.1056/NEJMoa2020283.
• "Genetic mechanisms of critical illness in Covid-19" by Pairo-Castineira, E., 23andMe, et al. 11 December 2020, Nature. DOI: 10.1038/s41586-020-03065-y.